A photoelectric conversion element using an organic material (organic photodiode) can effect photoelectric conversion of only a specific color (wavelength zone). Furthermore, since the photoelectric conversion element has such characteristic, in the case when it is used as a photoelectric conversion element in a solid-state imaging device, it can provide a structure in which subpixels are laminated, which cannot be obtained by a conventional solid-state imaging device comprising subpixels each comprising a combination of an on-chip color filter (OCCF) and a photoelectric conversion element, wherein the subpixels are arranged in a two-dimentional fashion. Therefore, incident light can be received at a high efficiency, and thus it is expected that the sensitivity of the solid-state imaging device is enhanced. Furthermore, the photoelectric conversion element has an advantage that it does not require demosaicing, and thus a false color is not generated.
On the other hand, an organic photoelectric conversion element used in a solid-state imaging device has an identical or similar structure to that of various organic thin film solar cells (for example, see JP 2006-339424 A, JP 2007-123707 A, JP 2007-311647 A and JP 2007-088033 A) and aims at improving a photoelectric conversion rate.